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CD12.11 Rother and Romney CFMP.pdf - Shepway District Council

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<strong>Rother</strong> <strong>and</strong> <strong>Romney</strong> Catchment<br />

Flood Management Plan<br />

Summary Report December 2009<br />

managing<br />

flood risk


We are the Environment Agency. It’s our job to look after<br />

your environment <strong>and</strong> make it a better place – for you,<br />

<strong>and</strong> for future generations.<br />

Your environment is the air you breathe, the water you<br />

drink <strong>and</strong> the ground you walk on. Working with business,<br />

Government <strong>and</strong> society as a whole, we are making your<br />

environment cleaner <strong>and</strong> healthier.<br />

The Environment Agency. Out there, making your<br />

environment a better place.<br />

Published by:<br />

Environment Agency<br />

Guildbourne House<br />

Chatsworth Road<br />

Worthing, West Sussex BN11 1LD<br />

Tel: 08708 506 506<br />

Email: enquiries@environment-agency.gov.uk<br />

www.environment-agency.gov.uk<br />

© Environment Agency<br />

All rights reserved. This document may be reproduced<br />

with prior permission of the Environment Agency.


Introduction<br />

I am pleased to introduce our summary of the<br />

<strong>Rother</strong> <strong>and</strong> <strong>Romney</strong> Catchment Flood Management<br />

Plan (<strong>CFMP</strong>). This <strong>CFMP</strong> gives an overview of the<br />

flood risk in the <strong>Rother</strong> <strong>and</strong> <strong>Romney</strong> catchment <strong>and</strong><br />

sets out our preferred plan for sustainable flood<br />

risk management over the next 50 to 100 years.<br />

The <strong>Rother</strong> <strong>and</strong> <strong>Romney</strong> <strong>CFMP</strong> is one of 77 <strong>CFMP</strong>s for<br />

Engl<strong>and</strong> <strong>and</strong> Wales. Through the <strong>CFMP</strong>s, we have<br />

assessed inl<strong>and</strong> flood risk across all of Engl<strong>and</strong> <strong>and</strong><br />

Wales for the first time. The <strong>CFMP</strong> considers all types of<br />

inl<strong>and</strong> flooding, from rivers, groundwater, surface<br />

water <strong>and</strong> tidal flooding, but not flooding directly from<br />

the sea (coastal flooding), which is covered by<br />

Shoreline Management Plans (SMPs). Our coverage of<br />

surface <strong>and</strong> groundwater is however limited due to a<br />

lack of available information.<br />

The role of <strong>CFMP</strong>s is to establish flood risk<br />

management policies which will deliver sustainable<br />

flood risk management for the long term. This is<br />

essential if we are to make the right investment<br />

decisions for the future <strong>and</strong> to help prepare ourselves<br />

effectively for the impact of climate change. We will<br />

use <strong>CFMP</strong>s to help us target our limited resources<br />

where the risks are greatest.<br />

This <strong>CFMP</strong> identifies flood risk management policies to<br />

assist all key decision makers in the catchment. It was<br />

produced through a wide consultation <strong>and</strong> appraisal<br />

process, however it is only the first step towards an<br />

integrated approach to flood risk management. As we<br />

all work together to achieve our objectives, we must<br />

monitor <strong>and</strong> listen to each others progress, discuss<br />

what has been achieved <strong>and</strong> consider where we may<br />

need to review parts of the <strong>CFMP</strong>.<br />

The main source of flood risk in the <strong>Rother</strong> <strong>and</strong> <strong>Romney</strong><br />

<strong>CFMP</strong> area is from both river <strong>and</strong> tidal flooding <strong>and</strong> to a<br />

lesser extent surface <strong>and</strong> ground water flooding. The<br />

main areas at risk from tidal flooding are Rye, Hythe,<br />

Folkestone, Hamstreet, Robertsbridge <strong>and</strong> Etchingham.<br />

We cannot reduce flood risk on our own, we will<br />

therefore work closely with all our partners to improve<br />

the co-ordination of flood risk activities <strong>and</strong> agree the<br />

most effective way to management flood risk in the<br />

future. The key partners we have worked with are Kent<br />

County <strong>Council</strong>, East Sussex County <strong>Council</strong>, <strong>Rother</strong><br />

<strong>District</strong> <strong>Council</strong>, <strong>Shepway</strong> <strong>District</strong> <strong>Council</strong>, Ashford<br />

Borough <strong>Council</strong>, <strong>Romney</strong> Marsh Internal Drainage<br />

Board, Natural Engl<strong>and</strong>, English Heritage, Southern<br />

Water, National Farmers Union.<br />

This is a summary of the main <strong>CFMP</strong> document, if you<br />

need to see the full document an electronic version<br />

can be obtained by emailing<br />

enquiries@environment-agency.gov.uk or alternatively<br />

paper copies can be viewed at any of our offices in<br />

Southern Region.<br />

Toby Willison<br />

Regional Director, Southern Region<br />

Environment Agency <strong>Rother</strong> <strong>and</strong> <strong>Romney</strong> Catchment Flood Management Plan 3


Contents<br />

The purpose of a <strong>CFMP</strong> in managing flood risk 5<br />

Catchment overview 6<br />

Current <strong>and</strong> future flood risk 8<br />

Future direction for flood risk management 11<br />

Sub-areas<br />

1 Robertsbridge <strong>and</strong> Etchingham 13<br />

2 Hamstreet 15<br />

3 <strong>Romney</strong> <strong>and</strong> Wall<strong>and</strong> Marshes 16<br />

4 Hythe <strong>and</strong> Folkestone 18<br />

5 Rye 20<br />

6 Rural <strong>Rother</strong> 21<br />

Map of <strong>CFMP</strong> policies 23<br />

4 Environment Agency <strong>Rother</strong> <strong>and</strong> <strong>Romney</strong> Catchment Flood Management Plan


The purpose of a <strong>CFMP</strong><br />

in managing flood risk<br />

<strong>CFMP</strong>s help us to underst<strong>and</strong> the<br />

scale <strong>and</strong> extent of flooding now<br />

<strong>and</strong> in the future, <strong>and</strong> set policies<br />

for managing flood risk within the<br />

catchment. <strong>CFMP</strong>s should be used<br />

to inform planning <strong>and</strong> decision<br />

making by key stakeholders such as:<br />

• The Environment Agency, who will<br />

use the plan to guide decisions<br />

on investment in further plans,<br />

projects or actions;<br />

• Regional planning bodies <strong>and</strong><br />

local authorities who can use the<br />

plan to inform spatial planning<br />

activities <strong>and</strong> emergency planning;<br />

• IDBs, water companies <strong>and</strong><br />

other utilities to help plan their<br />

activities in the wider context<br />

of the catchment;<br />

• Transportation planners;<br />

• L<strong>and</strong> owners, farmers <strong>and</strong><br />

l<strong>and</strong> managers that manage<br />

<strong>and</strong> operate l<strong>and</strong> for<br />

agriculture, conservation<br />

<strong>and</strong> amenity purposes;<br />

• The public <strong>and</strong> businesses to<br />

enhance their underst<strong>and</strong>ing<br />

of flood risk <strong>and</strong> how it will<br />

be managed.<br />

<strong>CFMP</strong>s aim to promote more<br />

sustainable approaches to managing<br />

flood risk. The policies identified in<br />

the <strong>CFMP</strong> will be delivered through a<br />

combination of different approaches.<br />

Together with our partners, we<br />

will implement these approaches<br />

through a range of delivery plans,<br />

projects <strong>and</strong> actions.<br />

The relationship between the <strong>CFMP</strong>,<br />

delivery plans, strategies, projects<br />

<strong>and</strong> actions is shown in figure 1.<br />

Figure 1. The relationship between <strong>CFMP</strong>s, delivery plans, projects <strong>and</strong> actions.<br />

Policy planning<br />

• <strong>CFMP</strong>s <strong>and</strong> Shoreline Management Plans.<br />

• Action plans define requirement for delivery<br />

plans, projects <strong>and</strong> actions.<br />

Policy delivery plans (see note)<br />

• Influence spatial planning to reduce risk<br />

<strong>and</strong> restore floodplains.<br />

• Prepare for <strong>and</strong> manage floods<br />

(including local flood warning plans).<br />

• Managing assets.<br />

• Water level management plans.<br />

• L<strong>and</strong> management <strong>and</strong> habitat creation.<br />

• Surface water management plans.<br />

Projects <strong>and</strong> actions<br />

• Make sure our spending delivers the best<br />

possible outcomes.<br />

• Focus on risk based targets, for example<br />

numbers of households at risk.<br />

Note: Some plans may not be led by us – we may<br />

identify the need <strong>and</strong> encourage their development.<br />

Environment Agency <strong>Rother</strong> <strong>and</strong> <strong>Romney</strong> Catchment Flood Management Plan 5


Catchment overview<br />

The <strong>CFMP</strong> area is situated in the<br />

South East of Engl<strong>and</strong>, covers<br />

approximately 970km2 with a<br />

population of 175,000 people.<br />

There are a number of towns within<br />

the <strong>CFMP</strong> area including Rye,<br />

Tenterden, Hythe, Dymchurch, Lydd,<br />

Robertsbridge <strong>and</strong> New <strong>Romney</strong><br />

with the major towns of Hastings<br />

<strong>and</strong> Folkestone at the edge of the<br />

<strong>CFMP</strong> area.<br />

The primary river system within the<br />

<strong>CFMP</strong> area is the River <strong>Rother</strong> along<br />

with its tributaries. The River <strong>Rother</strong><br />

rises near Mayfield in East Sussex<br />

<strong>and</strong> flows eastward extending<br />

through the towns of Robertsbridge<br />

<strong>and</strong> Etchingham. These towns have<br />

experienced severe flooding since<br />

the 1940s. The upper part of the<br />

catchment is mainly woodl<strong>and</strong> <strong>and</strong><br />

grassl<strong>and</strong>, but in some locations<br />

natural floodplains have been<br />

modified by farming <strong>and</strong> urban<br />

development with the result of<br />

increasing run-off to the lower part<br />

of the catchment. The lower <strong>and</strong><br />

eastern part of the catchment<br />

consists of a wide expanse of<br />

reclaimed coastal marshl<strong>and</strong> which<br />

lies mostly below the spring tide<br />

level.<br />

The geology of the area consist of<br />

alluvium <strong>and</strong> marine silts in the<br />

<strong>Rother</strong> <strong>and</strong> Wall<strong>and</strong> Marshes with<br />

Gault clay <strong>and</strong> Chalk in eastern<br />

extremity of <strong>Romney</strong> Marsh.<br />

Hastings Beds in the High Weald<br />

<strong>and</strong> shingle headl<strong>and</strong> of Dungeness<br />

extending into the English Channel.<br />

There are six sub-areas each with a<br />

preferred policy that divide the<br />

catchment area; the Robertsbridge<br />

<strong>and</strong> Etchingham, Hamstreet, Rye,<br />

<strong>Rother</strong> <strong>and</strong> Wall<strong>and</strong> Marshes, Hythe<br />

<strong>and</strong> Folkestone <strong>and</strong> Rural <strong>Rother</strong>.<br />

View south of rural <strong>Rother</strong> near<br />

Udimore, Kent.<br />

➜<br />

6 Environment Agency <strong>Rother</strong> <strong>and</strong> <strong>Romney</strong> Catchment Flood Management Plan


Map 1. Overview map of <strong>Rother</strong> <strong>and</strong> <strong>Romney</strong> catchment.<br />

‘The north <strong>and</strong> west of the <strong>Rother</strong> <strong>and</strong> <strong>Romney</strong><br />

catchment is part of the High Weald, mainly woodl<strong>and</strong>,<br />

grassl<strong>and</strong> <strong>and</strong> natural floodplains, while the south <strong>and</strong><br />

east are characterised by a wide expanse of reclaimed<br />

coastal marshl<strong>and</strong>.’<br />

Environment Agency <strong>Rother</strong> <strong>and</strong> <strong>Romney</strong> Catchment Flood Management Plan 7


➜<br />

Current <strong>and</strong> future flood risk<br />

Overview of the current<br />

flood risk<br />

Flood risk is the combination of the<br />

probability of flooding <strong>and</strong> its<br />

impact, that is, the chance of it<br />

happening <strong>and</strong> the consequences if<br />

it does happen. We have assessed<br />

flood risk across the <strong>CFMP</strong> area<br />

using broad-scale computer<br />

modelling, though making best use<br />

of existing knowledge <strong>and</strong> models<br />

where appropriate. Flood risk<br />

figures take into account current<br />

flood defences.<br />

The flood generation mechanism<br />

within the <strong>Rother</strong> <strong>and</strong> <strong>Romney</strong> <strong>CFMP</strong><br />

area varies in relation to both the<br />

watercourse <strong>and</strong> the location within<br />

the catchment. Significant flooding<br />

problems are associated with the<br />

urban areas of Robertsbridge,<br />

Etchingham <strong>and</strong> Hamstreet.<br />

Robertsbridge has suffered ever<br />

increasing flooding since 1946.<br />

Where is the risk?<br />

This map in page 10 illustrates the<br />

consequences of a 1% annual<br />

probability flood event (1 in 100<br />

year) occurring in the <strong>CFMP</strong> area.<br />

The areas with the highest<br />

concentration of properties at risk<br />

from river flooding are tabulated<br />

on page 9.<br />

Figure 2. Current <strong>and</strong> future (2100) flood risk to property from a 1% annual<br />

probability river flood, taking into account current flood defences.<br />

Number of properties at flood risk<br />

3000<br />

2500<br />

2000<br />

1500<br />

1000<br />

500<br />

0<br />

Current<br />

Robertsbridge <strong>and</strong><br />

Etchingham<br />

Future<br />

Hamstreet<br />

Hythe <strong>and</strong><br />

Folkestone<br />

Rye<br />

In the lower <strong>Rother</strong> catchment there<br />

are several minor tributaries <strong>and</strong><br />

drains that can cause isolated flood<br />

incidents <strong>and</strong> the <strong>Romney</strong> <strong>and</strong><br />

Wall<strong>and</strong> Marshes are prone to both<br />

river <strong>and</strong> coastal flooding.<br />

High waters on the River <strong>Rother</strong>.<br />

8 Environment Agency <strong>Rother</strong> <strong>and</strong> <strong>Romney</strong> Catchment Flood Management Plan


How we currently<br />

manage the risk<br />

The area is very low lying <strong>and</strong> there<br />

is a network of channels, drains,<br />

<strong>and</strong> structures which together with<br />

the Royal Military Canal combine to<br />

drain the area for agricultural use.<br />

There are also a number of small<br />

steep urban catchments <strong>and</strong><br />

existing defence infrastructure<br />

acts to defend the urban areas<br />

at risk. We are therefore looking<br />

for opportunities to revert the<br />

catchment back to its natural state.<br />

Our activity is prioritised on a risk<br />

basis <strong>and</strong> our main activities<br />

include:<br />

Table 1. Locations of towns <strong>and</strong> villages with 25 or more properties at risk<br />

in a 1% annual probability river flood.<br />

Number of properties at risk<br />

Table 2. Critical infrastructure at risk:<br />

Locations<br />

>1000 Rye, Hythe <strong>and</strong> Folkestone<br />

500 to 1000 None<br />

100 to 500 None<br />

50 to 100 Robertsbridge <strong>and</strong> Etchingham,<br />

Hamstreet<br />

25 to 50 None<br />

• Maintenance of existing <strong>and</strong><br />

commission of new flood<br />

defences <strong>and</strong> structures such as<br />

the flood alleviation scheme<br />

constructed 2003 in<br />

Robertsbridge. The scheme<br />

composed of approximately<br />

1,160 m of earth embankment,<br />

680 m of floodwalls <strong>and</strong> 430m<br />

of river realignment to protect<br />

the northern, central <strong>and</strong><br />

southern parts of the town from<br />

river flooding.<br />

• Flood forecasting <strong>and</strong> warnings,<br />

much of the data collected from<br />

the gauges that we operate,<br />

inform the flood warnings issued<br />

through the Flood Warnings<br />

Direct system to emergency<br />

services, parish councils,<br />

business <strong>and</strong> householders in<br />

key areas.<br />

1 emergency service, 6 schools<br />

Table 3. Designated sites at risk:<br />

Dungeness SAC<br />

• Development control, significant<br />

developments are not planned in<br />

the <strong>Rother</strong> <strong>and</strong> <strong>Romney</strong> <strong>CFMP</strong><br />

area. Any further developments<br />

must be supported by a flood<br />

risk assessment that also shows<br />

that the development will not<br />

increase flood risk elsewhere.<br />

• Flood risk mapping, has<br />

historically concentrated on the<br />

Rivers <strong>Rother</strong>, Darwell <strong>and</strong><br />

Dudwell. We are planning to<br />

develop a more accurate digital<br />

terrain model of the Marshes<br />

area to be used to estimate the<br />

extent, depth <strong>and</strong> duration of<br />

flooding, flood hazard <strong>and</strong> the<br />

river <strong>and</strong> coastal interactions.<br />

• Strategic planning to plan long<br />

term investment<br />

• Environmental improvements.<br />

Environment Agency <strong>Rother</strong> <strong>and</strong> <strong>Romney</strong> Catchment Flood Management Plan 9


Map 2. Flood risk to property in a 1% annual probability river flood, taking into account current flood defences.<br />

The impact of climate change <strong>and</strong> future flood risk<br />

The effect that flooding will have in<br />

the future is influenced by a range<br />

of issues such as climate change,<br />

changes in l<strong>and</strong> use such as<br />

development, <strong>and</strong> changes in how<br />

l<strong>and</strong> is managed.<br />

Predictions of future change are<br />

based on underst<strong>and</strong>ing the<br />

existing condition of the catchment,<br />

an extrapolation of trends over the<br />

long term (up to 100 years), <strong>and</strong> a<br />

high level review of likely future<br />

change based on research findings<br />

<strong>and</strong> knowledge. There are only a few<br />

sites identified for development<br />

within the catchment area, therefore<br />

the modelled impact of urbanisation<br />

on future flood risk in the <strong>Rother</strong> <strong>and</strong><br />

<strong>Romney</strong> <strong>CFMP</strong> area is negligible.<br />

L<strong>and</strong> use <strong>and</strong> l<strong>and</strong> use management<br />

changes such as afforestation could<br />

reduce peak flow <strong>and</strong> flood volume<br />

the upper <strong>Rother</strong> catchment,<br />

conversely, the likely effect of an<br />

agricultural intensification is to<br />

increase peak flow <strong>and</strong> flood volume<br />

upper parts of the catchment. From<br />

the three drivers tested, climate<br />

change has the largest impact on the<br />

<strong>Rother</strong> <strong>and</strong> <strong>Romney</strong> <strong>CFMP</strong> catchment<br />

with up to 20% increase in peak flood<br />

flows. This scenario is used to assess<br />

likely impacts in the catchment. In<br />

the <strong>Rother</strong> <strong>and</strong> <strong>Romney</strong> catchment<br />

the future flood risk is likely to be<br />

from river flooding <strong>and</strong> surface water<br />

flooding. Our appraisal of the future<br />

risk in the catchment reveals the<br />

number of properties at risk to the<br />

1% annual probability event will<br />

increase from 151 to 179 properties<br />

by the year 2100. The majority of<br />

these properties are located in<br />

Robertsbridge, Etchingham <strong>and</strong><br />

Hamstreet. Please note the broadscale<br />

modelling indicates there are large<br />

numbers of properties at risk in Rye,<br />

Hythe <strong>and</strong> Folkestone, however<br />

these figures do not differentiate<br />

between coastal <strong>and</strong> river flooding.<br />

The key trends are:<br />

• More frequent <strong>and</strong> intense<br />

storms causing more widespread<br />

<strong>and</strong> regular flooding from drainage<br />

systems <strong>and</strong> some rivers.<br />

• More rain in winter, increasing<br />

the likelihood of large scale<br />

flood events.<br />

10 Environment Agency <strong>Rother</strong> <strong>and</strong> <strong>Romney</strong> Catchment Flood Management Plan


Future direction for<br />

flood risk management<br />

Approaches in each sub-area<br />

We have divided the <strong>Rother</strong> <strong>and</strong> <strong>Romney</strong> catchment into six distinct<br />

sub-areas which have similar physical characteristics, sources of flooding<br />

<strong>and</strong> level of risk. We have identified the most appropriate approach to<br />

managing flood risk for each of the sub-areas <strong>and</strong> allocated one of six<br />

generic flood risk management policies, shown in Table 4.<br />

To select the most appropriate policy, the plan has considered how social,<br />

economic <strong>and</strong> environmental objectives are affected by flood risk<br />

management activities under each policy option.<br />

Map 3. Sub-areas <strong>and</strong> flood risk management policies.<br />

Environment Agency <strong>Rother</strong> <strong>and</strong> <strong>Romney</strong> Catchment Flood Management Plan 11


Table 4. Policy options.<br />

➜ Policy 1<br />

Areas of little or no flood risk where we will continue to monitor <strong>and</strong> advise<br />

This policy will tend to be applied in those areas where there are very few properties at risk of flooding. It reflects a<br />

commitment to work with the natural flood processes as far as possible.<br />

➜ Policy 2<br />

Areas of low to moderate flood risk where we can generally reduce existing flood risk management actions<br />

This policy will tend to be applied where the overall level of risk to people <strong>and</strong> property is low to moderate. It may<br />

no longer be value for money to focus on continuing current levels of maintenance of existing defences if we can<br />

use resources to reduce risk where there are more people at higher risk. We would therefore review the flood risk<br />

management actions being taken so that they are proportionate to the level of risk.<br />

➜ Policy 3<br />

Areas of low to moderate flood risk where we are generally managing existing flood risk effectively<br />

This policy will tend to be applied where the risks are currently appropriately managed <strong>and</strong> where the risk of<br />

flooding is not expected to increase significantly in the future. However, we keep our approach under review,<br />

looking for improvements <strong>and</strong> responding to new challenges or information as they emerge. We may review our<br />

approach to managing flood defences <strong>and</strong> other flood risk management actions, to ensure that we are managing<br />

efficiently <strong>and</strong> taking the best approach to managing flood risk in the longer term.<br />

➜ Policy 4<br />

Areas of low, moderate or high flood risk where we are already managing the flood risk effectively but where we<br />

may need to take further actions to keep pace with climate change<br />

This policy will tend to be applied where the risks are currently deemed to be appropriately-managed, but where<br />

the risk of flooding is expected to significantly rise in the future. In this case we would need to do more in the<br />

future to contain what would otherwise be increasing risk. Taking further action to reduce risk will require further<br />

appraisal to assess whether there are socially <strong>and</strong> environmentally sustainable, technically viable <strong>and</strong><br />

economically justified options.<br />

➜ Policy 5<br />

Areas of moderate to high flood risk where we can generally take further action to reduce flood risk<br />

This policy will tend to be applied to those areas where the case for further action to reduce flood risk is most<br />

compelling, for example where there are many people at high risk, or where changes in the environment have<br />

already increased risk. Taking further action to reduce risk will require additional appraisal to assess whether there<br />

are socially <strong>and</strong> environmentally sustainable, technically viable <strong>and</strong> economically justified options.<br />

➜ Policy 6<br />

Areas of low to moderate flood risk where we will take action with others to store water or manage run-off in<br />

locations that provide overall flood risk reduction or environmental benefits<br />

This policy will tend to be applied where there may be opportunities in some locations to reduce flood risk locally<br />

or more widely in a catchment by storing water or managing run-off. The policy has been applied to an area (where<br />

the potential to apply the policy exists), but would only be implemented in specific locations within the area, after<br />

more detailed appraisal <strong>and</strong> consultation.<br />

12 Environment Agency <strong>Rother</strong> <strong>and</strong> <strong>Romney</strong> Catchment Flood Management Plan


Sub-area 1<br />

Robertsbridge <strong>and</strong> Etchingham<br />

Our key partners are:<br />

<strong>Rother</strong> <strong>District</strong> <strong>Council</strong><br />

Impact of a 1% annual probability flood event<br />

Today Future (2100)<br />

Number of properties at risk 65 83<br />

The issues in this<br />

sub-area<br />

The Etchingham <strong>and</strong> Robertsbridge<br />

sub-area covers these villages<br />

situated on the <strong>Rother</strong>. The sub-area<br />

extends approximately one<br />

kilometre upstream of the<br />

confluence of the Rivers <strong>Rother</strong> <strong>and</strong><br />

Darwell, to approximately one<br />

kilometre downstream of the A21<br />

crossing in Robertsbridge.<br />

The impact on flooding of new<br />

development depends on the<br />

implementation of Sustainable urban<br />

Drainage Systems (SuDS), which is of<br />

particular importance as surface<br />

water flooding due to overloaded<br />

drainage is already a problem.<br />

The vision <strong>and</strong><br />

preferred policy<br />

Policy Option 3 – areas of low to<br />

moderate flood risk where we are<br />

generally managing existing flood<br />

risk effectively.<br />

➜<br />

Robertsbridge<br />

flood alleviation<br />

scheme.<br />

Environment Agency <strong>Rother</strong> <strong>and</strong> <strong>Romney</strong> Catchment Flood Management Plan 13


The key messages<br />

The chosen policy will aim to maintain the numbers of properties <strong>and</strong> people considered to be at flood risk <strong>and</strong> the<br />

duration <strong>and</strong> severity of impacts upon transport, infrastructure, public assets <strong>and</strong> amenities.<br />

It is important that there is no increase in surface water run-off from new development <strong>and</strong> existing development.<br />

Therefore we must seek opportunities to reduce run-off.<br />

Proposed actions to implement the preferred approach:<br />

• Provide Development Control advice to ensure no increase in run-off from new developments <strong>and</strong> seek<br />

opportunities to reduce current run-off rates where appropriate. Limited development in the floodplain is<br />

planned in this policy unit.<br />

• Develop a System Asset Management Plan (SAMP). This plan should aim to maintain flood risk at the<br />

current level.<br />

Robertsbridge<br />

flood alleviation<br />

scheme.<br />

➜<br />

14 Environment Agency <strong>Rother</strong> <strong>and</strong> <strong>Romney</strong> Catchment Flood Management Plan


➜<br />

Sub-area 2<br />

Hamstreet<br />

Our key partners are:<br />

Ashford Borough <strong>Council</strong><br />

Southern Water<br />

Impact of a 1% annual probability flood event<br />

Today Future (2100)<br />

Number of properties at risk 79 96<br />

The issues in this<br />

sub-area<br />

The Hamstreet policy unit covers<br />

this small urban area to the<br />

confluence of the Speringbrook<br />

Sewer with the Royal Military Canal.<br />

Flooding in Hamstreet is caused by<br />

a combination of river, surface <strong>and</strong><br />

groundwater sources. The<br />

Speringbrook Sewer <strong>and</strong> other<br />

surface water channels flow through<br />

the town draining a small clay<br />

catchment. Due to the nature of the<br />

clay soil <strong>and</strong> low lying l<strong>and</strong>,<br />

groundwater levels are close to the<br />

surface <strong>and</strong> storms can produce<br />

flooding very quickly, generating<br />

high water levels in the<br />

Speringbrook Sewer. Insufficient<br />

capacity of the local drainage<br />

system then causes flooding in<br />

several areas of Hamstreet.<br />

The vision <strong>and</strong><br />

preferred policy<br />

Policy Option 3 – areas of low to<br />

moderate flood risk where we are<br />

generally managing existing flood<br />

risk effectively.<br />

The key messages<br />

The chosen policy will aim to<br />

maintain the numbers of properties<br />

<strong>and</strong> people considered to be at<br />

flood risk <strong>and</strong> the duration <strong>and</strong><br />

severity of impacts upon transport,<br />

infrastructure, public assets <strong>and</strong><br />

amenities.<br />

It is important that there is no<br />

increase in surface water run-off<br />

from new development <strong>and</strong> existing<br />

development seek to reduce run-off.<br />

Maintenance of assets ought to<br />

ensure the current st<strong>and</strong>ard of<br />

protection is upheld to<br />

accommodate flooding due to<br />

climate change.<br />

Duck pond at Hamstreet.<br />

Proposed actions to<br />

implement the preferred<br />

approach:<br />

• We will need to work with Ashford<br />

Borough <strong>Council</strong> <strong>and</strong> Southern<br />

Water to develop Surface Water<br />

Management Plan (SWMP) for<br />

Hamstreet. This will address<br />

surface water flows <strong>and</strong> the link<br />

between the Speringbrook Sewer<br />

<strong>and</strong> the Royal Military Canal.<br />

• Undertake System Asset<br />

Management Plans (SAMPs) to<br />

review maintenance regimes <strong>and</strong><br />

to maintain current level of<br />

investment.<br />

• Provide development control<br />

advice to ensure no increase in<br />

run-off from new developments<br />

<strong>and</strong> seek opportunities to reduce<br />

current run-off rates where<br />

appropriate. There has been<br />

recent <strong>and</strong> extensive<br />

development in this unit.<br />

Environment Agency <strong>Rother</strong> <strong>and</strong> <strong>Romney</strong> Catchment Flood Management Plan 15


➜<br />

Sub-area 3<br />

<strong>Romney</strong> <strong>and</strong><br />

Wall<strong>and</strong> Marshes<br />

Our key partners are:<br />

<strong>Rother</strong> <strong>District</strong> <strong>Council</strong><br />

Ashford Borough <strong>Council</strong> <strong>and</strong><br />

<strong>Shepway</strong> <strong>District</strong> <strong>Council</strong><br />

Natural Engl<strong>and</strong><br />

Internal Drainage Board<br />

Impact of a 1% annual probability flood event<br />

Today Future (2100)<br />

Number of properties at risk Minimal Minimal<br />

The issues in this<br />

sub-area<br />

This policy unit covers the low lying<br />

areas of <strong>Romney</strong> <strong>and</strong> Wall<strong>and</strong><br />

Marshes, including <strong>and</strong> bounded by<br />

the Royal Military Canal to the north<br />

<strong>and</strong> east, <strong>and</strong> the outfall of the<br />

<strong>Rother</strong> to the south. The Nickolls<br />

Quarry site is included within this<br />

policy unit. The area is very low lying<br />

<strong>and</strong> flat. The flood risk is complex,<br />

as the area is at risk of from both<br />

river <strong>and</strong> coastal flooding. A<br />

complex network of drains <strong>and</strong><br />

management of water levels in the<br />

Royal Military Canal control water<br />

movement within the Marshes. The<br />

current level of flood risk from river<br />

flooding is relatively low in this<br />

area, <strong>and</strong> the number of properties<br />

within this policy unit affected by<br />

river flooding is minimal.<br />

The vision <strong>and</strong><br />

preferred policy<br />

Policy Option 3 – areas of low to<br />

moderate flood risk where we are<br />

generally managing existing flood<br />

risk effectively.<br />

View across Wall<strong>and</strong> Marsh.<br />

16 Environment Agency <strong>Rother</strong> <strong>and</strong> <strong>Romney</strong> Catchment Flood Management Plan


➜<br />

The key messages<br />

The chosen policy supports economic <strong>and</strong> social sustainability by prioritising significant gains elsewhere with the<br />

acceptance for some potential for future minor losses within the sub-area.<br />

Proposed actions to implement the preferred approach:<br />

• Undertake System Asset Management Plans (SAMPs) to review maintenance regimes <strong>and</strong> to maintain curent<br />

level of investment.<br />

• We will need to week with Natural Engl<strong>and</strong> to create wetl<strong>and</strong> habitat.<br />

• Support the development <strong>and</strong> recommendations of the Wall<strong>and</strong> Marsh, Dungeness <strong>Romney</strong> Marsh, Rye Bay<br />

<strong>and</strong> <strong>Romney</strong> Warren Water Level Management Plans (WLMPs).<br />

• Undertake depth, duration <strong>and</strong> hazard mapping on <strong>Romney</strong> Marsh, including looking at coastal <strong>and</strong> river<br />

interactions. To improve the underst<strong>and</strong>ing of flood depths <strong>and</strong> hazard on the marshes.<br />

Outfall at Dymchurch, <strong>Romney</strong> <strong>and</strong> Wall<strong>and</strong> Marshes.<br />

Environment Agency <strong>Rother</strong> <strong>and</strong> <strong>Romney</strong> Catchment Flood Management Plan 17


Sub-area 4<br />

Hythe <strong>and</strong> Folkestone<br />

Our key partners are:<br />

<strong>Shepway</strong> <strong>District</strong> <strong>Council</strong><br />

Southern Water<br />

The issues in this<br />

sub-area<br />

This policy unit covers the urban<br />

area of Hythe, <strong>and</strong> the area of<br />

Folkestone which is not part of the<br />

Stour <strong>CFMP</strong>. This is a small urban<br />

policy unit. Current predictions are<br />

for storm intensity to increase due<br />

to climate change, therefore flood<br />

risk is expected to increase in<br />

the future.<br />

Impact of a 1% annual probability flood event<br />

Today Future (2100)<br />

Number of properties at risk 2085 2444*<br />

*Figures are predominantly due to coastal flooding <strong>and</strong> excludes the<br />

presence of flood defences. Derived from floodzone 3 which does not<br />

distinguish between river <strong>and</strong> coastal flooding.<br />

The vision <strong>and</strong><br />

preferred policy<br />

Policy Option 4 – areas of low,<br />

moderate or high flood risk where<br />

we are already managing the flood<br />

risk effectively but where we may<br />

need to take further actions to keep<br />

pace with climate change.<br />

➜<br />

Royal Military Canal looking west,<br />

through Hythe.<br />

18 Environment Agency <strong>Rother</strong> <strong>and</strong> <strong>Romney</strong> Catchment Flood Management Plan


➜<br />

The key messages<br />

This policy applies where the current risk is acceptable but future changes are expected to have a significant<br />

impact. Flood risk management activities need to respond to the potential increases in flood risk.<br />

Proposed actions to implement the preferred approach:<br />

• Improve underst<strong>and</strong>ing of the watercourses that were previously ordinary watercourses within this policy unit.<br />

• We will need to work with <strong>Shepway</strong> <strong>District</strong> <strong>Council</strong> to develop a System Asset Management Plan (SAMP).<br />

This plan should aim to maintain flood risk at the existing level taking climate change into account.<br />

• We will need to work with Southern Water <strong>and</strong> <strong>Shepway</strong> <strong>District</strong> <strong>Council</strong> to develop a Surface Water<br />

Management Plan (SWMP) for Folkestone <strong>and</strong> Hythe.<br />

• Provide development control advice to ensure no increase in run-off from new developments <strong>and</strong> seek<br />

opportunities to reduce current run-off rates where appropriate.<br />

Royal Military canal looking east, through Hythe.<br />

Environment Agency <strong>Rother</strong> <strong>and</strong> <strong>Romney</strong> Catchment Flood Management Plan 19


➜<br />

Sub-area 5<br />

Rye<br />

Our key partners are:<br />

<strong>Rother</strong> <strong>District</strong> <strong>Council</strong><br />

Southern Water<br />

Natural Engl<strong>and</strong><br />

The issues in this<br />

sub-area<br />

The Rye policy unit covers this urban<br />

area at the confluence of the Rivers<br />

<strong>Rother</strong>, Brede <strong>and</strong> Tillingham. Flood<br />

risk in Rye is high, with approximately<br />

1,190 properties lying within the 1 in<br />

100 year flood event floodplain (note<br />

that this does not distinguish<br />

between river <strong>and</strong> coastal flooding,<br />

<strong>and</strong> excludes the presence of flood<br />

defences). Flooding is largely<br />

caused by rivers, although tide<br />

locking effects can be significant <strong>and</strong><br />

will increase with rising sea levels.<br />

The vision <strong>and</strong><br />

preferred policy<br />

Policy Option 4 – areas of low,<br />

moderate or high flood risk where<br />

we are already managing the flood<br />

risk effectively but where we may<br />

need to take further actions to keep<br />

pace with climate change.<br />

Impact of a 1% annual probability flood event<br />

Today Future (2100)<br />

Number of properties at risk 1190 1428*<br />

*Future scenario figure extrapolated from similar cathment modelling in<br />

Southern region.<br />

Proposed actions to implement the preferred<br />

approach:<br />

• Provide development control advice to ensure no increase in run-off<br />

from new developments <strong>and</strong> seek opportunities to reduce current<br />

run-off rates where appropriate. Considerable l<strong>and</strong> is required for<br />

development in this policy unit.<br />

• Develop a System Asset Management Plan (SAMP). This plan should<br />

aim to maintain flood risk at the existing level taking climate change<br />

into account.<br />

• We will need to work in partnership with <strong>Rother</strong> <strong>District</strong> <strong>Council</strong> <strong>and</strong><br />

Southern Water to develop a Surface Water Management Plan (SWMP)<br />

for Rye. This will address the important issue of surface water flooding<br />

in this unit.<br />

• Support the development <strong>and</strong> recommendations of the Rye Harbour<br />

SSSI Water Level Management Plan (WLMP). Support the development<br />

of the WLMP for the new Dungeness, <strong>Romney</strong> Marsh <strong>and</strong> Rye Bay Site of<br />

Special Scientific Interest (SSSI). Water Level Management Plans are key<br />

for managing flood risk <strong>and</strong> biodiversity needs in this unit.<br />

The key messages<br />

This policy applies where the current<br />

risk is acceptable but future changes<br />

are expected to have a significant<br />

impact. Flood risk management<br />

activities need to respond to the<br />

potential increases in flood risk.<br />

Sluice Gate on the River Tillingham, Rye.<br />

20 Environment Agency <strong>Rother</strong> <strong>and</strong> <strong>Romney</strong> Catchment Flood Management Plan


➜<br />

Sub-area 6<br />

Rural <strong>Rother</strong><br />

Our key partners are:<br />

Wealden <strong>District</strong> <strong>Council</strong><br />

<strong>Rother</strong> <strong>District</strong> <strong>Council</strong><br />

Ashford Borough <strong>Council</strong><br />

Tunbridge Wells Borough <strong>Council</strong><br />

<strong>Shepway</strong> <strong>District</strong> <strong>Council</strong><br />

Natural Engl<strong>and</strong><br />

Internal Drainage Board<br />

The issues in this<br />

sub-area<br />

This policy unit covers areas of the<br />

<strong>Rother</strong> <strong>and</strong> <strong>Romney</strong> <strong>CFMP</strong> that are<br />

not covered by the other policy<br />

units. In the past there has been<br />

little or no risk of flooding from<br />

rivers, surface water or foul water<br />

flooding. Three to four properties<br />

have been known to flood from the<br />

Marsham Sewer at the base of Chick<br />

Hill, near Cliff End.<br />

Impact of a 1% annual probability flood event<br />

Today Future (2100)<br />

Number of properties at risk Minimal Minimal<br />

The vision <strong>and</strong><br />

preferred policy<br />

Policy Option 6 – areas of low to<br />

moderate flood risk where we will<br />

take action with others to store<br />

water or manage run-off in locations<br />

that provide overall flood risk<br />

reduction or environmental<br />

benefits.<br />

The key messages<br />

River flood risk is low. We will seek<br />

opportunities for more sustainable<br />

flood risk management activities in<br />

this policy unit.<br />

View North across Rural <strong>Rother</strong>, near Udimore village.<br />

Environment Agency <strong>Rother</strong> <strong>and</strong> <strong>Romney</strong> Catchment Flood Management Plan 21


➜<br />

Proposed actions to implement the preferred approach:<br />

• Support the development <strong>and</strong> recommendations of the Rye Harbour <strong>and</strong> Pett Level SSSI Water Level<br />

Management Plans (WLMP). Support the development of the WLMP for the new Dungeness, <strong>Romney</strong> Marsh <strong>and</strong><br />

Rye Bay Sites of Special Scientific Interest (SSSI). WLMPs are key for managing flood risk <strong>and</strong> biodiversity needs<br />

in this unit.<br />

• Develop a System Asset Management Plan (SAMP). This plan should aim to increase the frequency of flooding<br />

to deliver benefits elsewhere. For example, investigate areas identified in the High Weald integrated catchment<br />

management <strong>and</strong> river restoration study where wetl<strong>and</strong> habitat or washl<strong>and</strong>s can help to reduce flooding.<br />

(Link with the regional habitat creation programme, River <strong>Rother</strong> restoration strategy <strong>and</strong> <strong>Rother</strong> - the potential<br />

for the integrated management of rural floodplains project).<br />

• Investigate opportunities to work with l<strong>and</strong>owners to create wetl<strong>and</strong> habitat, The High Weald integrated<br />

catchment management <strong>and</strong> river restoration study should be updated with data review <strong>and</strong> ground truthing<br />

to prioritise sites for further investigation. (Link with the regional habitat creation programme, River <strong>Rother</strong><br />

restoration strategy <strong>and</strong> <strong>Rother</strong>- the potential for the integrated management of rural floodplains project).<br />

Flooded fields within Rural <strong>Rother</strong>, off the Udimore road.<br />

22 Environment Agency <strong>Rother</strong> <strong>and</strong> <strong>Romney</strong> Catchment Flood Management Plan


Map of <strong>CFMP</strong> policies<br />

Map of the policies in the <strong>Rother</strong> <strong>and</strong> <strong>Romney</strong> catchment.<br />

Environment Agency <strong>Rother</strong> <strong>and</strong> <strong>Romney</strong> Catchment Flood Management Plan 23


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or about your environment?<br />

Then call us on<br />

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email<br />

enquiries@environment-agency.gov.uk<br />

or visit our website<br />

www.environment-agency.gov.uk<br />

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